In the US, 75% of people would identify themselves as Christians whereas only 30% of scientists would do the same. Why are Christians so poorly represented in science? Is there a bias against Christians in the American college system? The authors of this paper conduct studies into whether college professors rate students less favourably when students reveal a Christian, religious identity. Their findings conclude that there is a perceived bias against Christians and this could account for the relatively small proportion of Christians in science. However, the actual bias is only toward a certain sort of Christian that could be described as fundamentalist or evangelical. See the article here.